When a gas generating agent is used in an inflator for use in a safety apparatus for a vehicle such as a airbag apparatus disposed in a vehicle, it is very important to improve ignition ability of the gas generating agent in order to ensure product reliability.
And, it is important to decrease the combustion temperature of the gas generating agent because the heat load on the coolant disposed in the inflator can be reduced and an amount of the coolant can be decreased.
However, where the combustion temperature of the gas generating agent is decreased too much, the ignition ability is degraded. Therefore, it is desirable to decrease the combustion temperature and obtain excellent ignition ability at the same time.
Further, depending on the season or region, a vehicle can be exposed for a long time to high-temperature environment, and therefore it is also required that a gas generating agent in an inflator have high heat resistance.
JP-B No. 3907548 discloses a gas generating composition for an inflator including: (a) melamine cyanurate or a mixture of melamine cyanurate and a nitrogen-containing organic compound as a fuel, and (b) an oxygen-containing oxidizing agent, which can exhibit a specific effect such as a low combustion temperature and a small amount of generated hazardous gas, as a result of using novel melamine cyanurate as a fuel component.
It is described that the compounding ratio (mass ratio), nitrogen-containing organic compound/melamine cyanurate in the mixture of melamine cyanurate and nitrogen-containing organic compound is preferably 0.05 to 8, more preferably 0.1 to 6, and even more preferably 0.2 to 2. In this case, when the ratio of the nitrogen-containing organic compound/melamine cyanurate is 0.2 to 2, the content of melamine cyanurate is 33.3 to 83.3% by mass and the content of nitroguanidine is 16.7 to 66.7% by mass.
Decreasing combustion temperature is described as a problem to be solved, but improving ignition ability is not a problem to be solved, and it is only described that the ignition ability is improved by selecting an appropriate binder.